Guy Ritchie is the worst screenwriter in the world, but, to be fair, he is not the worst director. He is only the worst director of the people who actually get to make movies. As we speak, there are human beings walking the Earth - perhaps as many as a half dozen of them - with less directorial talent, but they've been safely diverted into other activities.

The good news is that "Sherlock Holmes" is the finest movie Ritchie has ever made, and that's because he didn't write the script. The bad news is that despite a good script, a good story and a great actor - Robert Downey Jr. - not to mention a seriously strong cast, including Jude Law and Rachel McAdams - Ritchie still only delivers what is, at best, a break-even proposition. This is a director who can't get out of his own way.

Yet peel away the clutter, and the movie's reconception of Holmes has merit. In this version, he is a sensitive neurotic who completely falls apart between cases. He stays in his room and doesn't wash, and his only contact with the world is Watson, who is not a bumbler (like Nigel Bruce in the old movies), but a handsome and capable fellow, a physician and a war hero. In fact, Holmes depends on Watson so much that he is terrified of losing him and does his best to sabotage Watson's relationships with women.

Furthermore, in this reimagining, Holmes' capacity for deductive reasoning is not a form of intellectual genius but something else - a quirk of mind, a hypersensitivity to all forms of stimuli that makes life difficult, almost hellish. It's the one thing Ritchie does well, but he only does it once: When Holmes steps out into the world, he is bombarded by information from every direction.

All this probably sounds like the description of a very good movie, but it's not the one that Ritchie has made. These finer elements are there, but they're buried under long-drawn-out fight scenes, in which Holmes and Watson, armed with their walking sticks (and Watson's gun) fight it out with ... oh, a whole bunch of people. Who can keep track?

In this film publicity image released by Warner Bros. Pictures, Robert Downey Jr., left, and Rachel McAdams are shown in a scene from "Sherlock Holmes." (AP Photo/Warner Bros. Pictures, Alex Bailey)

In this film publicity image released by Warner Bros. Pictures, Robert Downey Jr., left, and Rachel McAdams are shown in a scene from "Sherlock Holmes." (AP Photo/Warner Bros. Pictures, Alex Bailey)

Photo: ALEX BAILEY, AP

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In this film publicity image released by Warner Bros. Pictures, Robert Downey Jr., left, and Jude Law are shown in a scene from "Sherlock Holmes." (AP Photo/Warner Bros. Pictures)

In this film publicity image released by Warner Bros. Pictures, Robert Downey Jr., left, and Jude Law are shown in a scene from "Sherlock Holmes." (AP Photo/Warner Bros. Pictures)

Photo: Associated Press

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Review: Weak Ritchie hurts 'Sherlock Holmes'

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There's also the question of tone. As in Ritchie's other movies, all scenes are played for flippancy and archness, that peculiar brand of convoluted breeziness that has become Ritchie's signature. Nothing is funny, and yet nothing is to be taken seriously. In terms of storytelling, everything is a wash. Important information isn't lifted out, just tossed off and given equal weight with everything else. So it takes about an hour to lock onto the fact that there's an actual story going on and that, guess what, it's fairly interesting.

It concerns a magician (played by Mark Strong, a powerful character actor), who is hanged but won't stay dead. This sort of case might not have fazed Basil Rathbone, but it's especially trying for Downey's Holmes, whose hold on sanity is shaky to begin with. He has to lean on Watson (as played by Jude Law, Watson is not the funny one but the straight man). Holmes' mental state also makes him prey to the seductive charm of career criminal Irene Adler (McAdams).

"Sherlock Holmes" will probably spark a franchise, and it's one with genuine potential. But for a franchise to thrive, it's going to need a reasonably good director. A very good director would be ideal, but just a halfway decent one might do the trick.

-- Advisory: This film contains violence.

To hear Mick LaSalle talk about movies, listen to his weekly podcast at sfgate.com/podcasts.